We transfected plasmid expressing wild-type ADAR1-p150 protein and plasmid expressing mutant type ADAR1-p150 (▲ E/A) protein, an RNA-editing inactive form of ADAR1 in which glutamate was changed to alanine, into breast cancer cell lines, respectively, to detect METTL3 mRNA levels. The gene discussed is METTL3; the disease is breast cancer.